drivers/usb/gadget/function/f_serial.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * f_serial.c - generic USB serial function driver
  *
  * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
  * Copyright (C) 2008 by David Brownell
  * Copyright (C) 2008 by Nokia Corporation
  */

 #include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/device.h>

 #include "u_serial.h"


 /*
  * This function packages a simple "generic serial" port with no real
  * control mechanisms, just raw data transfer over two bulk endpoints.
  *
  * Because it's not standardized, this isn't as interoperable as the
  * CDC ACM driver.  However, for many purposes it's just as functional
  * if you can arrange appropriate host side drivers.
  */

 struct f_gser {
 	struct gserial			port;
 	u8				data_id;
 	u8				port_num;
 };

 static inline struct f_gser *func_to_gser(struct usb_function *f)
 {
 	return container_of(f, struct f_gser, port.func);
 }

 /*-------------------------------------------------------------------------*/

 /* interface descriptor: */

 static struct usb_interface_descriptor gser_interface_desc = {
 	.bLength =		USB_DT_INTERFACE_SIZE,
 	.bDescriptorType =	USB_DT_INTERFACE,
 	/* .bInterfaceNumber = DYNAMIC */
 	.bNumEndpoints =	2,
 	.bInterfaceClass =	USB_CLASS_VENDOR_SPEC,
 	.bInterfaceSubClass =	0,
 	.bInterfaceProtocol =	0,
 	/* .iInterface = DYNAMIC */
 };

 /* full speed support: */

 static struct usb_endpoint_descriptor gser_fs_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bEndpointAddress =	USB_DIR_IN,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 };

 static struct usb_endpoint_descriptor gser_fs_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bEndpointAddress =	USB_DIR_OUT,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 };

 static struct usb_descriptor_header *gser_fs_function[] = {
 	(struct usb_descriptor_header *) &gser_interface_desc,
 	(struct usb_descriptor_header *) &gser_fs_in_desc,
 	(struct usb_descriptor_header *) &gser_fs_out_desc,
 	NULL,
 };

 /* high speed support: */

 static struct usb_endpoint_descriptor gser_hs_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 	.wMaxPacketSize =	cpu_to_le16(512),
 };

 static struct usb_endpoint_descriptor gser_hs_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 	.wMaxPacketSize =	cpu_to_le16(512),
 };

 static struct usb_descriptor_header *gser_hs_function[] = {
 	(struct usb_descriptor_header *) &gser_interface_desc,
 	(struct usb_descriptor_header *) &gser_hs_in_desc,
 	(struct usb_descriptor_header *) &gser_hs_out_desc,
 	NULL,
 };

 static struct usb_endpoint_descriptor gser_ss_in_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 	.wMaxPacketSize =	cpu_to_le16(1024),
 };

 static struct usb_endpoint_descriptor gser_ss_out_desc = {
 	.bLength =		USB_DT_ENDPOINT_SIZE,
 	.bDescriptorType =	USB_DT_ENDPOINT,
 	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
 	.wMaxPacketSize =	cpu_to_le16(1024),
 };

 static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
 	.bLength =              sizeof gser_ss_bulk_comp_desc,
 	.bDescriptorType =      USB_DT_SS_ENDPOINT_COMP,
 };

 static struct usb_descriptor_header *gser_ss_function[] = {
 	(struct usb_descriptor_header *) &gser_interface_desc,
 	(struct usb_descriptor_header *) &gser_ss_in_desc,
 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
 	(struct usb_descriptor_header *) &gser_ss_out_desc,
 	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
 	NULL,
 };

 /* string descriptors: */

 static struct usb_string gser_string_defs[] = {
 	[0].s = "Generic Serial",
 	{  } /* end of list */
 };

 static struct usb_gadget_strings gser_string_table = {
 	.language =		0x0409,	/* en-us */
 	.strings =		gser_string_defs,
 };

 static struct usb_gadget_strings *gser_strings[] = {
 	&gser_string_table,
 	NULL,
 };

 /*-------------------------------------------------------------------------*/

 static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 {
 	struct f_gser		*gser = func_to_gser(f);
 	struct usb_composite_dev *cdev = f->config->cdev;

 	/* we know alt == 0, so this is an activation or a reset */

 	if (gser->port.in->enabled) {
 		dev_dbg(&cdev->gadget->dev,
 			"reset generic ttyGS%d\n", gser->port_num);
 		gserial_disconnect(&gser->port);
 	}
 	if (!gser->port.in->desc || !gser->port.out->desc) {
 		dev_dbg(&cdev->gadget->dev,
 			"activate generic ttyGS%d\n", gser->port_num);
 		if (config_ep_by_speed(cdev->gadget, f, gser->port.in) ||
 		    config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
 			gser->port.in->desc = NULL;
 			gser->port.out->desc = NULL;
 			return -EINVAL;
 		}
 	}
 	gserial_connect(&gser->port, gser->port_num);
 	return 0;
 }

 static void gser_disable(struct usb_function *f)
 {
 	struct f_gser	*gser = func_to_gser(f);
 	struct usb_composite_dev *cdev = f->config->cdev;

 	dev_dbg(&cdev->gadget->dev,
 		"generic ttyGS%d deactivated\n", gser->port_num);
 	gserial_disconnect(&gser->port);
 }

 /*-------------------------------------------------------------------------*/

 /* serial function driver setup/binding */

 static int gser_bind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct usb_composite_dev *cdev = c->cdev;
 	struct f_gser		*gser = func_to_gser(f);
 	int			status;
 	struct usb_ep		*ep;

 	/* REVISIT might want instance-specific strings to help
 	 * distinguish instances ...
 	 */

 	/* maybe allocate device-global string ID */
 	if (gser_string_defs[0].id == 0) {
 		status = usb_string_id(c->cdev);
 		if (status < 0)
 			return status;
 		gser_string_defs[0].id = status;
 	}

 	/* allocate instance-specific interface IDs */
 	status = usb_interface_id(c, f);
 	if (status < 0)
 		goto fail;
 	gser->data_id = status;
 	gser_interface_desc.bInterfaceNumber = status;

 	status = -ENODEV;

 	/* allocate instance-specific endpoints */
 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
 	if (!ep)
 		goto fail;
 	gser->port.in = ep;

 	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
 	if (!ep)
 		goto fail;
 	gser->port.out = ep;

 	/* support all relevant hardware speeds... we expect that when
 	 * hardware is dual speed, all bulk-capable endpoints work at
 	 * both speeds
 	 */
 	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

 	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
 	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

 	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
 			gser_ss_function, gser_ss_function);
 	if (status)
 		goto fail;
 	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: IN/%s OUT/%s\n",
 		gser->port_num,
 		gser->port.in->name, gser->port.out->name);
 	return 0;

 fail:
 	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);

 	return status;
 }

 static inline struct f_serial_opts *to_f_serial_opts(struct config_item *item)
 {
 	return container_of(to_config_group(item), struct f_serial_opts,
 			    func_inst.group);
 }

 static void serial_attr_release(struct config_item *item)
 {
 	struct f_serial_opts *opts = to_f_serial_opts(item);

 	usb_put_function_instance(&opts->func_inst);
 }

 static struct configfs_item_operations serial_item_ops = {
 	.release	= serial_attr_release,
 };

 #ifdef CONFIG_U_SERIAL_CONSOLE

 static ssize_t f_serial_console_store(struct config_item *item,
 		const char *page, size_t count)
 {
 	return gserial_set_console(to_f_serial_opts(item)->port_num,
 				   page, count);
 }

 static ssize_t f_serial_console_show(struct config_item *item, char *page)
 {
 	return gserial_get_console(to_f_serial_opts(item)->port_num, page);
 }

 CONFIGFS_ATTR(f_serial_, console);

 #endif /* CONFIG_U_SERIAL_CONSOLE */

 static ssize_t f_serial_port_num_show(struct config_item *item, char *page)
 {
 	return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
 }

 CONFIGFS_ATTR_RO(f_serial_, port_num);

 static struct configfs_attribute *acm_attrs[] = {
 #ifdef CONFIG_U_SERIAL_CONSOLE
 	&f_serial_attr_console,
 #endif
 	&f_serial_attr_port_num,
 	NULL,
 };

 static const struct config_item_type serial_func_type = {
 	.ct_item_ops	= &serial_item_ops,
 	.ct_attrs	= acm_attrs,
 	.ct_owner	= THIS_MODULE,
 };

 static void gser_free_inst(struct usb_function_instance *f)
 {
 	struct f_serial_opts *opts;

 	opts = container_of(f, struct f_serial_opts, func_inst);
 	gserial_free_line(opts->port_num);
 	kfree(opts);
 }

 static struct usb_function_instance *gser_alloc_inst(void)
 {
 	struct f_serial_opts *opts;
 	int ret;

 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
 	if (!opts)
 		return ERR_PTR(-ENOMEM);

 	opts->func_inst.free_func_inst = gser_free_inst;
 	ret = gserial_alloc_line(&opts->port_num);
 	if (ret) {
 		kfree(opts);
 		return ERR_PTR(ret);
 	}
 	config_group_init_type_name(&opts->func_inst.group, "",
 				    &serial_func_type);

 	return &opts->func_inst;
 }

 static void gser_free(struct usb_function *f)
 {
 	struct f_gser *serial;

 	serial = func_to_gser(f);
 	kfree(serial);
 }

 static void gser_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_gser	*gser = func_to_gser(f);

 	/* Ensure port is disconnected before unbinding */
 	gserial_disconnect(&gser->port);
 	usb_free_all_descriptors(f);
 }

 static void gser_resume(struct usb_function *f)
 {
 	struct f_gser *gser = func_to_gser(f);

 	gserial_resume(&gser->port);
 }

 static void gser_suspend(struct usb_function *f)
 {
 	struct f_gser *gser = func_to_gser(f);

 	gserial_suspend(&gser->port);
 }

 static struct usb_function *gser_alloc(struct usb_function_instance *fi)
 {
 	struct f_gser	*gser;
 	struct f_serial_opts *opts;

 	/* allocate and initialize one new instance */
 	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
 	if (!gser)
 		return ERR_PTR(-ENOMEM);

 	opts = container_of(fi, struct f_serial_opts, func_inst);

 	gser->port_num = opts->port_num;

 	gser->port.func.name = "gser";
 	gser->port.func.strings = gser_strings;
 	gser->port.func.bind = gser_bind;
 	gser->port.func.unbind = gser_unbind;
 	gser->port.func.set_alt = gser_set_alt;
 	gser->port.func.disable = gser_disable;
 	gser->port.func.free_func = gser_free;
 	gser->port.func.resume = gser_resume;
 	gser->port.func.suspend = gser_suspend;

 	return &gser->port.func;
 }

 DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Al Borchers");
 MODULE_AUTHOR("David Brownell");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* f_serial.c - generic USB serial function driver
	*
	* Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
	* Copyright (C) 2008 by David Brownell
	* Copyright (C) 2008 by Nokia Corporation
	*/

	#include <linux/slab.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/device.h>

	#include "u_serial.h"


	/*
	* This function packages a simple "generic serial" port with no real
	* control mechanisms, just raw data transfer over two bulk endpoints.
	*
	* Because it's not standardized, this isn't as interoperable as the
	* CDC ACM driver. However, for many purposes it's just as functional
	* if you can arrange appropriate host side drivers.
	*/

	struct f_gser {
	struct gserial port;
	u8 data_id;
	u8 port_num;
	};

	static inline struct f_gser func_to_gser(struct usb_function f)
	{
	return container_of(f, struct f_gser, port.func);
	}

	/-------------------------------------------------------------------------/

	/* interface descriptor: */

	static struct usb_interface_descriptor gser_interface_desc = {
	.bLength = USB_DT_INTERFACE_SIZE,
	.bDescriptorType = USB_DT_INTERFACE,
	/* .bInterfaceNumber = DYNAMIC */
	.bNumEndpoints = 2,
	.bInterfaceClass = USB_CLASS_VENDOR_SPEC,
	.bInterfaceSubClass = 0,
	.bInterfaceProtocol = 0,
	/* .iInterface = DYNAMIC */
	};

	/* full speed support: */

	static struct usb_endpoint_descriptor gser_fs_in_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = USB_DIR_IN,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	};

	static struct usb_endpoint_descriptor gser_fs_out_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bEndpointAddress = USB_DIR_OUT,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	};

	static struct usb_descriptor_header *gser_fs_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_fs_in_desc,
	(struct usb_descriptor_header *) &gser_fs_out_desc,
	NULL,
	};

	/* high speed support: */

	static struct usb_endpoint_descriptor gser_hs_in_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize = cpu_to_le16(512),
	};

	static struct usb_endpoint_descriptor gser_hs_out_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize = cpu_to_le16(512),
	};

	static struct usb_descriptor_header *gser_hs_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_hs_in_desc,
	(struct usb_descriptor_header *) &gser_hs_out_desc,
	NULL,
	};

	static struct usb_endpoint_descriptor gser_ss_in_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize = cpu_to_le16(1024),
	};

	static struct usb_endpoint_descriptor gser_ss_out_desc = {
	.bLength = USB_DT_ENDPOINT_SIZE,
	.bDescriptorType = USB_DT_ENDPOINT,
	.bmAttributes = USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize = cpu_to_le16(1024),
	};

	static struct usb_ss_ep_comp_descriptor gser_ss_bulk_comp_desc = {
	.bLength = sizeof gser_ss_bulk_comp_desc,
	.bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
	};

	static struct usb_descriptor_header *gser_ss_function[] = {
	(struct usb_descriptor_header *) &gser_interface_desc,
	(struct usb_descriptor_header *) &gser_ss_in_desc,
	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
	(struct usb_descriptor_header *) &gser_ss_out_desc,
	(struct usb_descriptor_header *) &gser_ss_bulk_comp_desc,
	NULL,
	};

	/* string descriptors: */

	static struct usb_string gser_string_defs[] = {
	[0].s = "Generic Serial",
	{ } /* end of list */
	};

	static struct usb_gadget_strings gser_string_table = {
	.language = 0x0409, /* en-us */
	.strings = gser_string_defs,
	};

	static struct usb_gadget_strings *gser_strings[] = {
	&gser_string_table,
	NULL,
	};

	/-------------------------------------------------------------------------/

	static int gser_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
	{
	struct f_gser *gser = func_to_gser(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	/* we know alt == 0, so this is an activation or a reset */

	if (gser->port.in->enabled) {
	dev_dbg(&cdev->gadget->dev,
	"reset generic ttyGS%d\n", gser->port_num);
	gserial_disconnect(&gser->port);
	}
	if (!gser->port.in->desc \|\| !gser->port.out->desc) {
	dev_dbg(&cdev->gadget->dev,
	"activate generic ttyGS%d\n", gser->port_num);
	if (config_ep_by_speed(cdev->gadget, f, gser->port.in) \|\|
	config_ep_by_speed(cdev->gadget, f, gser->port.out)) {
	gser->port.in->desc = NULL;
	gser->port.out->desc = NULL;
	return -EINVAL;
	}
	}
	gserial_connect(&gser->port, gser->port_num);
	return 0;
	}

	static void gser_disable(struct usb_function *f)
	{
	struct f_gser *gser = func_to_gser(f);
	struct usb_composite_dev *cdev = f->config->cdev;

	dev_dbg(&cdev->gadget->dev,
	"generic ttyGS%d deactivated\n", gser->port_num);
	gserial_disconnect(&gser->port);
	}

	/-------------------------------------------------------------------------/

	/* serial function driver setup/binding */

	static int gser_bind(struct usb_configuration c, struct usb_function f)
	{
	struct usb_composite_dev *cdev = c->cdev;
	struct f_gser *gser = func_to_gser(f);
	int status;
	struct usb_ep *ep;

	/* REVISIT might want instance-specific strings to help
	* distinguish instances ...
	*/

	/* maybe allocate device-global string ID */
	if (gser_string_defs[0].id == 0) {
	status = usb_string_id(c->cdev);
	if (status < 0)
	return status;
	gser_string_defs[0].id = status;
	}

	/* allocate instance-specific interface IDs */
	status = usb_interface_id(c, f);
	if (status < 0)
	goto fail;
	gser->data_id = status;
	gser_interface_desc.bInterfaceNumber = status;

	status = -ENODEV;

	/* allocate instance-specific endpoints */
	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_in_desc);
	if (!ep)
	goto fail;
	gser->port.in = ep;

	ep = usb_ep_autoconfig(cdev->gadget, &gser_fs_out_desc);
	if (!ep)
	goto fail;
	gser->port.out = ep;

	/* support all relevant hardware speeds... we expect that when
	* hardware is dual speed, all bulk-capable endpoints work at
	* both speeds
	*/
	gser_hs_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
	gser_hs_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

	gser_ss_in_desc.bEndpointAddress = gser_fs_in_desc.bEndpointAddress;
	gser_ss_out_desc.bEndpointAddress = gser_fs_out_desc.bEndpointAddress;

	status = usb_assign_descriptors(f, gser_fs_function, gser_hs_function,
	gser_ss_function, gser_ss_function);
	if (status)
	goto fail;
	dev_dbg(&cdev->gadget->dev, "generic ttyGS%d: IN/%s OUT/%s\n",
	gser->port_num,
	gser->port.in->name, gser->port.out->name);
	return 0;

	fail:
	ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);

	return status;
	}

	static inline struct f_serial_opts to_f_serial_opts(struct config_item item)
	{
	return container_of(to_config_group(item), struct f_serial_opts,
	func_inst.group);
	}

	static void serial_attr_release(struct config_item *item)
	{
	struct f_serial_opts *opts = to_f_serial_opts(item);

	usb_put_function_instance(&opts->func_inst);
	}

	static struct configfs_item_operations serial_item_ops = {
	.release = serial_attr_release,
	};

	#ifdef CONFIG_U_SERIAL_CONSOLE

	static ssize_t f_serial_console_store(struct config_item *item,
	const char *page, size_t count)
	{
	return gserial_set_console(to_f_serial_opts(item)->port_num,
	page, count);
	}

	static ssize_t f_serial_console_show(struct config_item item, char page)
	{
	return gserial_get_console(to_f_serial_opts(item)->port_num, page);
	}

	CONFIGFS_ATTR(f_serial_, console);

	#endif /* CONFIG_U_SERIAL_CONSOLE */

	static ssize_t f_serial_port_num_show(struct config_item item, char page)
	{
	return sprintf(page, "%u\n", to_f_serial_opts(item)->port_num);
	}

	CONFIGFS_ATTR_RO(f_serial_, port_num);

	static struct configfs_attribute *acm_attrs[] = {
	#ifdef CONFIG_U_SERIAL_CONSOLE
	&f_serial_attr_console,
	#endif
	&f_serial_attr_port_num,
	NULL,
	};

	static const struct config_item_type serial_func_type = {
	.ct_item_ops = &serial_item_ops,
	.ct_attrs = acm_attrs,
	.ct_owner = THIS_MODULE,
	};

	static void gser_free_inst(struct usb_function_instance *f)
	{
	struct f_serial_opts *opts;

	opts = container_of(f, struct f_serial_opts, func_inst);
	gserial_free_line(opts->port_num);
	kfree(opts);
	}

	static struct usb_function_instance *gser_alloc_inst(void)
	{
	struct f_serial_opts *opts;
	int ret;

	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
	if (!opts)
	return ERR_PTR(-ENOMEM);

	opts->func_inst.free_func_inst = gser_free_inst;
	ret = gserial_alloc_line(&opts->port_num);
	if (ret) {
	kfree(opts);
	return ERR_PTR(ret);
	}
	config_group_init_type_name(&opts->func_inst.group, "",
	&serial_func_type);

	return &opts->func_inst;
	}

	static void gser_free(struct usb_function *f)
	{
	struct f_gser *serial;

	serial = func_to_gser(f);
	kfree(serial);
	}

	static void gser_unbind(struct usb_configuration c, struct usb_function f)
	{
	struct f_gser *gser = func_to_gser(f);

	/* Ensure port is disconnected before unbinding */
	gserial_disconnect(&gser->port);
	usb_free_all_descriptors(f);
	}

	static void gser_resume(struct usb_function *f)
	{
	struct f_gser *gser = func_to_gser(f);

	gserial_resume(&gser->port);
	}

	static void gser_suspend(struct usb_function *f)
	{
	struct f_gser *gser = func_to_gser(f);

	gserial_suspend(&gser->port);
	}

	static struct usb_function gser_alloc(struct usb_function_instance fi)
	{
	struct f_gser *gser;
	struct f_serial_opts *opts;

	/* allocate and initialize one new instance */
	gser = kzalloc(sizeof(*gser), GFP_KERNEL);
	if (!gser)
	return ERR_PTR(-ENOMEM);

	opts = container_of(fi, struct f_serial_opts, func_inst);

	gser->port_num = opts->port_num;

	gser->port.func.name = "gser";
	gser->port.func.strings = gser_strings;
	gser->port.func.bind = gser_bind;
	gser->port.func.unbind = gser_unbind;
	gser->port.func.set_alt = gser_set_alt;
	gser->port.func.disable = gser_disable;
	gser->port.func.free_func = gser_free;
	gser->port.func.resume = gser_resume;
	gser->port.func.suspend = gser_suspend;

	return &gser->port.func;
	}

	DECLARE_USB_FUNCTION_INIT(gser, gser_alloc_inst, gser_alloc);
	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Al Borchers");
	MODULE_AUTHOR("David Brownell");